Add Docker release workflow for automated image builds (#105)

### TL;DR

Added a GitHub Actions workflow for Docker image release

### What changed?

- Created a new GitHub Actions workflow file `.github/workflows/docker-release.yml` for automated Docker image building and pushing on release events.
- The workflow uses Docker Buildx, logs into Docker Hub, extracts metadata, and builds/pushes the image with appropriate tags and labels.

### How to test?

1. Create a new release or manually trigger the workflow.
2. Verify that the GitHub Action runs successfully.
3. Check Docker Hub to ensure the new image is pushed with the correct tags.

### Why make this change?

This change automates the Docker image release process, ensuring consistent and reliable deployments. It streamlines the release workflow, reducing manual intervention and potential errors during the release process.

.dockerignore

@@ -1,4 +1,4 @@
 .env
 .mockery.yaml
 
-configs/secrets*
+configs/secrets*

.github/workflows/docker-release.yml

@@ -0,0 +1,39 @@
+name: Docker Release
+
+on:
+  release:
+    types: [published]
+  workflow_dispatch:
+
+env:
+  DOCKER_IMAGE: thirdweb/indexer
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.DOCKER_IMAGE }}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

Dockerfile

@@ -21,4 +21,4 @@ EXPOSE 8080
 
 ENTRYPOINT ["/bin/app"]
 
-CMD []
+CMD []